quiksilver81
New member
heres everything you need to know about a supercharger pretty much. http://www.popularhotrodding.com/enginemasters/articles/hardcore/0411em_super/index.html
Size of a supercharger and other questions
- Thread starter quiksilver81
- Start date
So question for you guys. Is a centrifugal supercharger the most compact of the super chargers? And if not the most compact, the most conveniently shaped charger out there?
I wanna put a twin-screw supercharger (Whipple), but there really isn't any space underneath my hood. I think the only option I have is a centrifugal charger.
Now, I've read the difference between the 3 main kinds of super chargers: centrifugal, roots, and twin screw, but I'm wondering if anyone who has used 2 or 3 of the 3, can tell me the difference between in terms of driving experience, longevity, etc, and which would they prefer.
I wanna put a twin-screw supercharger (Whipple), but there really isn't any space underneath my hood. I think the only option I have is a centrifugal charger.
Now, I've read the difference between the 3 main kinds of super chargers: centrifugal, roots, and twin screw, but I'm wondering if anyone who has used 2 or 3 of the 3, can tell me the difference between in terms of driving experience, longevity, etc, and which would they prefer.
the other pc
New member
The article is a nice overview. I sure wouldn’t recommend anybody take on a project with that alone. A lot more info is needed to do an installation that actually works.
I believe you’re right, I don’t think I’ve seen any currently available mechanically driven superchargers out there smaller than centrifugal units.
That’s one way to go. vdog0531 makes a good point about changing the hood.
I haven’t used any of them so I can’t give a first hand account, just vicious rumor and innuendo.
Supercharger can be generally classed into two types, positive displacement and dynamic. In real world terms commercially available positive displacement compressors, Roots, twin screw, sliding vane, etc have all been mechanically driven. The only commercially available dynamic types have been radial flow centrifugal compressors, both mechanically driven and exhaust gas driven (turbo).
In vague general terms centrifugal compressors are more efficient than positive displacement types and theoretically can deliver greater performance. In practical terms that theoretical advantage is limited to a narrow range of operating conditions. In the real world it’s not so simple but as a general rule of thumb centrifugal compressors usually have lower performance in the low to mid rev ranges and excel in the higher ranges while positive displacement systems can often be tuned for a broader torque curve.
The only guy I know with a supercharged daily driver has a factory stock Pontiac Grand Prix with the 3.8L V6 and Roots (Eaton) blower. The blower drive bearings puked after around 30k miles and the dealer had to replace the entire unit. Luckily he had an extended warranty that covered it. Don't know how common that is, maybe he just got lucky.
PC.
BMW645 said:
I believe you’re right, I don’t think I’ve seen any currently available mechanically driven superchargers out there smaller than centrifugal units.
BMW645 said:
That’s one way to go. vdog0531 makes a good point about changing the hood.
BMW645 said:
I haven’t used any of them so I can’t give a first hand account, just vicious rumor and innuendo.
Supercharger can be generally classed into two types, positive displacement and dynamic. In real world terms commercially available positive displacement compressors, Roots, twin screw, sliding vane, etc have all been mechanically driven. The only commercially available dynamic types have been radial flow centrifugal compressors, both mechanically driven and exhaust gas driven (turbo).
In vague general terms centrifugal compressors are more efficient than positive displacement types and theoretically can deliver greater performance. In practical terms that theoretical advantage is limited to a narrow range of operating conditions. In the real world it’s not so simple but as a general rule of thumb centrifugal compressors usually have lower performance in the low to mid rev ranges and excel in the higher ranges while positive displacement systems can often be tuned for a broader torque curve.
The only guy I know with a supercharged daily driver has a factory stock Pontiac Grand Prix with the 3.8L V6 and Roots (Eaton) blower. The blower drive bearings puked after around 30k miles and the dealer had to replace the entire unit. Luckily he had an extended warranty that covered it. Don't know how common that is, maybe he just got lucky.
PC.
i think it all depends on your engine. like for the ford modular V-8s, you can stick the supercharger in the valley area, and it won't stick up too much. but centrifugal s/c's can be installed in different ways.
i have no personal experience with S/C's, but the differences i've heard is that centrifugal builds power progessively, sort of like a turbo. so as the rpms build, so does the power. with roots/twin screw, the power is pretty much instantaneous. between the roots and twin screw, the twin screw is suppose to be more efficient.
which one is better varies on a bunch of factors and depends on the intended use.
i have no personal experience with S/C's, but the differences i've heard is that centrifugal builds power progessively, sort of like a turbo. so as the rpms build, so does the power. with roots/twin screw, the power is pretty much instantaneous. between the roots and twin screw, the twin screw is suppose to be more efficient.
which one is better varies on a bunch of factors and depends on the intended use.
I know a number of people with supercharged daily drivers. I have one, my Miata; I have a Roots style, positive displacement. I'm not sure, but I think there are a couple people here that supercharged their trucks.
PC is right, there are so many variables that make one choice right for this driver and a different choice right for that driver. If you haven't been to marque-specific forums yet, that's what I recommend.
Tom
PC is right, there are so many variables that make one choice right for this driver and a different choice right for that driver. If you haven't been to marque-specific forums yet, that's what I recommend.
Tom
jfox03cobra
New member
2003 cobra's come supercharged from the factory with a roots type blower. Roots type and twinc screws have great low end torque compared to centri-type blowers. Roots being less efficient than a twin screws type. For example...the stock blower on my cobra is an Eaton m112 roots type. I could bolt on a Kenne Bell or Whipple (both twin screw type) and probably make close to 50 more rwhp (and maybe torque) at the same boost level just because it's more efficient. The great thing w/roots and twin screws is as soon as you hit the gas the torque is there. (Belt driven) Centri-type superchargers take time to spool and will give more high end horsepower...I've never owned or driven a car with one so I can't say how they feel/drive.
If I had a choice I'd go turbo since they are probably the most efficient of them all. Mainly because it uses exhaust your car already produces instead of requiring belts (which robs power to drive them). One of the main negatives of a turbo is all the fabrication and work it requires to install one, plus it's generally more expensive.
Here's a good example of turbo car vs twin screws car (03 cobra). Look at the boost they are both running (its the second race).
http://www.racingsouthwest.com/~buffhomer/KBvsGTvsTT.wmv
Here's an example of a roots type torque curve. See how as soon as you hit the gas the torque is there.
If I had a choice I'd go turbo since they are probably the most efficient of them all. Mainly because it uses exhaust your car already produces instead of requiring belts (which robs power to drive them). One of the main negatives of a turbo is all the fabrication and work it requires to install one, plus it's generally more expensive.
Here's a good example of turbo car vs twin screws car (03 cobra). Look at the boost they are both running (its the second race).
http://www.racingsouthwest.com/~buffhomer/KBvsGTvsTT.wmv
Here's an example of a roots type torque curve. See how as soon as you hit the gas the torque is there.
My experience with blowers has taken me through three styles.
Centri - Roots - TS.
My Procharger centri leaked oil. I had issues with leaky seals, they were never fixed and when my motor blew up I sold it. It made very good power, power that came in from 3000 rpm and pulled all the way up to 6000. It was an awesome sensation when I was getting close to the top end. I also had very good TQ numbers but the seal problem really left a bad taste in my mouth. I hated the look of having a big lump sitting off to the side of my motor; to me it doesn't look like it belongs.
My MP90 (Saleen kit) looked more natural on top of the motor. This kit didn't make a ton of power, the intake design is terrible. I did however have more fun driving my car with this blower because of the low end power. As I stated earlier the Procharger pulled very hard through the top end, the PDB came in much earlier and even though it had 30 RWHP less it felt just as quick. However, it did lose a lot of power on top because the blower produces more heat at higher RPM's.
My newest project is still within the PDB family, it's a Whipple 2.3l TS. I have yet to fire it up but given my past experience with the Saleen kit I'm thinking that this may be my "holy grail" LOL - again, the low end power, instant throttle response and this time I should be able to keep that power through the top end. TS blowers unlike the Roots style compress air, Roots style blowers are basically a pump, the rotor design moves air through the blower but against the case, this creates a lot of heat. TS's on the other hand actually compress the air within the screws, this allows for cooler temps, and require less HP to actually turn the blower.
As for longevity, like anything else maintenance is the key. Centri's by their nature IMO are more likely to break only because the impellers turn at such a high rpm, this causes a lot of heat inside and in turn takes a toll on bearings and seals. However, if you monitor the oil levels you should catch any problem before they arise.
Roots style, well they are used by car manufactures on production vehicles; they have a very good history of being reliable and meeting OEM testing.
I know that some manufactures use TS blowers on their production vehicles but I haven't really seen a whole lot. I believe that this is due to the cost of manufacturing a TS, the rotor design is very unique, and requires special machines to fabricate them. Last time I checked there were only three of these machines in existence - that could have changed but I haven't done any research to verify that.
I think that you also need to be aware that if you decide to take an engineered kit and build upon it you will have to adjust things like injectors, fuel pump(s), Mass air, and tuning. Don't overlook these items, especially the tuning part, they are very important to having a good experience with blower.
Here is a picture of my Whipple for a size reference. This is in a late model Mustang.
Centri - Roots - TS.
My Procharger centri leaked oil. I had issues with leaky seals, they were never fixed and when my motor blew up I sold it. It made very good power, power that came in from 3000 rpm and pulled all the way up to 6000. It was an awesome sensation when I was getting close to the top end. I also had very good TQ numbers but the seal problem really left a bad taste in my mouth. I hated the look of having a big lump sitting off to the side of my motor; to me it doesn't look like it belongs.
My MP90 (Saleen kit) looked more natural on top of the motor. This kit didn't make a ton of power, the intake design is terrible. I did however have more fun driving my car with this blower because of the low end power. As I stated earlier the Procharger pulled very hard through the top end, the PDB came in much earlier and even though it had 30 RWHP less it felt just as quick. However, it did lose a lot of power on top because the blower produces more heat at higher RPM's.
My newest project is still within the PDB family, it's a Whipple 2.3l TS. I have yet to fire it up but given my past experience with the Saleen kit I'm thinking that this may be my "holy grail" LOL - again, the low end power, instant throttle response and this time I should be able to keep that power through the top end. TS blowers unlike the Roots style compress air, Roots style blowers are basically a pump, the rotor design moves air through the blower but against the case, this creates a lot of heat. TS's on the other hand actually compress the air within the screws, this allows for cooler temps, and require less HP to actually turn the blower.
As for longevity, like anything else maintenance is the key. Centri's by their nature IMO are more likely to break only because the impellers turn at such a high rpm, this causes a lot of heat inside and in turn takes a toll on bearings and seals. However, if you monitor the oil levels you should catch any problem before they arise.
Roots style, well they are used by car manufactures on production vehicles; they have a very good history of being reliable and meeting OEM testing.
I know that some manufactures use TS blowers on their production vehicles but I haven't really seen a whole lot. I believe that this is due to the cost of manufacturing a TS, the rotor design is very unique, and requires special machines to fabricate them. Last time I checked there were only three of these machines in existence - that could have changed but I haven't done any research to verify that.
I think that you also need to be aware that if you decide to take an engineered kit and build upon it you will have to adjust things like injectors, fuel pump(s), Mass air, and tuning. Don't overlook these items, especially the tuning part, they are very important to having a good experience with blower.
Here is a picture of my Whipple for a size reference. This is in a late model Mustang.
Attachments
JasonD
New member
There has been some great info on this topic so far, so I will just add a little bit of my experiences for you.
I've been around forced induction of various types for about the last ten years, and have seen just about everything.
I will give you an outline of what to expect from each one with pros and cons for each one as well. I will tell you now, the bottom line here is what your intended purpose is going to be for this application and they style of driving you prefer.
Centrifugal - Number one choice for absolute power. A lot of people feel the centrifugal blower doesn't have much bottom end torque, which can be true with a very small blower, but when you get into the larger ones this becomes an issue of the past. Out of the group, this is the most efficient one because it creates the least amount of heat. 8lbs of boost from a centrifugal will product the same amount of power that a twin screw will at 10lbs, and a roots at 12lbs. The more psi you need to make the power you want, the more pressure, wear, and tear you are putting on your engine.
I had a Vortech blower on my 99' Expedition and I spoke to the guy I sold it to recently and he still has it on there, and has just over 60,000 miles on it with not a single problem.....not a single leak, squeak, or hiccup and it makes a consistent 8 psi whenever you hit the pedal.
Pros - Awesome horsepower, and all around torque. Very efficient, and easy to install. I installed the ones on my Expedition and Mustang in less than one day each. I'm currently running a Vortech T-trim on my Mustang @ 22psi with no aftercooler, and not a single problem.
Cons - If you just bolt on one of the kits available without optimizing the boost pressure with pulley changes, etc. you will feel that they lack some bottom end torque, especially when compared to the other two types. Again, they more than make up for this though with top end power.
Roots - Great bottom end torque but these are the least efficient out of the group since they create the absolute most heat ever. I think of them as great big heat sinks.
Pros - I've seen these mounted in very tight spaces, and they have great bottom end power.
Cons - Massive heat buildup, and runs out of steam extremely fast. Don't even think about overspinning one of these or you will end up with a hole in a piston. They are good for 14psi, and that's about it (purely judging from the ones I've seen).
Twin Screw - This is the one that is giving the centrifugal world a run for it's money. They have both awesome bottom end torque and top end horsepower. I've seen these make 25lbs of boost with not aftercooler and still be rather efficient. I don't consider this one to be quite as efficient as a centrifugal, nor do they have as much top end horsepower but they make up for this with bottom end torque.
Pros - Enough torque to give you wiplash, fairly easy to install since it sits right on top of the intake.
Cons - Adds a lot of height to the engine (as stated earlier), and creates a good bit of heat when leaned on with higher boost pressures. Last but not least, all this bottom end torque will KILL your tires, and will almost make all this added power useless.
Here's my take on all this. For a street driven car, I'd go with a twin screw hands down. For a drag race car, I'd go with a centrifugal hand's down. For my competition's car, I'd go with a roots.
All of this being said, every single one of these blowers can be made more efficient by adding an aftercooler of some sort. The colder you can make the inlet air temp. the better off you'll be. In addition to an aftercooler, you can also add a small shot of nitrous which does the same thing but in the combustion chamber. I'm not talking about a lot, just enough to cool things down and it makes a tremendous amount of power.
Last but not least. I don't care what power adder you buy, if you don't get your car tuned correctly, you will have nothing but problems and will never be happy. It's all in the tuning, remember that.
I've been around forced induction of various types for about the last ten years, and have seen just about everything.
I will give you an outline of what to expect from each one with pros and cons for each one as well. I will tell you now, the bottom line here is what your intended purpose is going to be for this application and they style of driving you prefer.
Centrifugal - Number one choice for absolute power. A lot of people feel the centrifugal blower doesn't have much bottom end torque, which can be true with a very small blower, but when you get into the larger ones this becomes an issue of the past. Out of the group, this is the most efficient one because it creates the least amount of heat. 8lbs of boost from a centrifugal will product the same amount of power that a twin screw will at 10lbs, and a roots at 12lbs. The more psi you need to make the power you want, the more pressure, wear, and tear you are putting on your engine.
I had a Vortech blower on my 99' Expedition and I spoke to the guy I sold it to recently and he still has it on there, and has just over 60,000 miles on it with not a single problem.....not a single leak, squeak, or hiccup and it makes a consistent 8 psi whenever you hit the pedal.
Pros - Awesome horsepower, and all around torque. Very efficient, and easy to install. I installed the ones on my Expedition and Mustang in less than one day each. I'm currently running a Vortech T-trim on my Mustang @ 22psi with no aftercooler, and not a single problem.
Cons - If you just bolt on one of the kits available without optimizing the boost pressure with pulley changes, etc. you will feel that they lack some bottom end torque, especially when compared to the other two types. Again, they more than make up for this though with top end power.
Roots - Great bottom end torque but these are the least efficient out of the group since they create the absolute most heat ever. I think of them as great big heat sinks.
Pros - I've seen these mounted in very tight spaces, and they have great bottom end power.
Cons - Massive heat buildup, and runs out of steam extremely fast. Don't even think about overspinning one of these or you will end up with a hole in a piston. They are good for 14psi, and that's about it (purely judging from the ones I've seen).
Twin Screw - This is the one that is giving the centrifugal world a run for it's money. They have both awesome bottom end torque and top end horsepower. I've seen these make 25lbs of boost with not aftercooler and still be rather efficient. I don't consider this one to be quite as efficient as a centrifugal, nor do they have as much top end horsepower but they make up for this with bottom end torque.
Pros - Enough torque to give you wiplash, fairly easy to install since it sits right on top of the intake.
Cons - Adds a lot of height to the engine (as stated earlier), and creates a good bit of heat when leaned on with higher boost pressures. Last but not least, all this bottom end torque will KILL your tires, and will almost make all this added power useless.
Here's my take on all this. For a street driven car, I'd go with a twin screw hands down. For a drag race car, I'd go with a centrifugal hand's down. For my competition's car, I'd go with a roots.
All of this being said, every single one of these blowers can be made more efficient by adding an aftercooler of some sort. The colder you can make the inlet air temp. the better off you'll be. In addition to an aftercooler, you can also add a small shot of nitrous which does the same thing but in the combustion chamber. I'm not talking about a lot, just enough to cool things down and it makes a tremendous amount of power.
Last but not least. I don't care what power adder you buy, if you don't get your car tuned correctly, you will have nothing but problems and will never be happy. It's all in the tuning, remember that.
JDookie said:There has been some great info on this topic so far, so I will just add a little bit of my experiences for you.
Here's my take on all this. For a street driven car, I'd go with a twin screw hands down. For a drag race car, I'd go with a centrifugal hand's down. For my competition's car, I'd go with a roots.
Last but not least. I don't care what power adder you buy, if you don't get your car tuned correctly, you will have nothing but problems and will never be happy. It's all in the tuning, remember that.
Thanks guys for all the information. Now, when you placed this charger in, how did you get your car tuned? Did you go to a tuner? Or did you do it yourself? How do you change the fuel/air mixture maps? Can you even get any sort of performance boost by install a blower without changing your air/fuel mixture?
Also, I got a V8 car, how bad would the parasitic lag be? Is it even noticeable on a V8 car, even after getting it 'chipped'? I mean, you can chip your car to get like an extra 30HP, then put the charger in. The charger would give say, -20hp lag. But when considering both, you still get at least 10HP throughout the whole RPM range, right?
Is that how it works?
Also, what's a good book to learn the basics of combustion engines, but then takes me to an intermediary level of knowledge? Thanks.
JasonD
New member
BMW645 said:
Whatever you do, do NOT buy a chip or programmer that is programmed for a non-supercharged car. You will blow something up if you do.
Most supercharger kits will come with whatever tools needed to reprogram (tune) your car. Companies like Vortech and Procharger will provide a tuner like a Diablo Sport Predator in the kit which is preprogrammed for your specific application, if it's even needed at all because sometimes it's not.
That being said, you can further your car's capability by getting a *custom* tune. The absolute best way to get the most out of your car will be to go to a tuner shop that has an in-house dyno and custom tuning capabilities. My friend owns one here, but that won't do you any good.
In my opinion, the absolute best tuning technology is coming from Superchips. They just recently released their new wave of tuning technology, which includes two versions. You can either get a chip with or without a 4-position switch for changes on the fly or you can get a hand-held programmer kind of like the Predator BUT the difference here is that the Superchips product will be a full custom tune. You can probably get something like this from the Diablo Sport Predator, but I'm not sure. Regardless, it's the four position switch that can be changed *on the fly* that's appealing to me. You can have a stock setting, highway setting, power setting, etc. and change it whenever you want without even slowing down.
You can't do this with the tuners.
Gains from a custom tune vs. a standard base tune can be anywhere from 0-150hp depending on the application, and depending on the person who is doing the tuning can most of the time make the combination even safer than without the tune.
I suggest going on the Superchips website and giving them a call when you are ready to find out where the closest *certified* custom tuner is to where you live, and go there.
As far as "lag", I don't really find that there is much. The "lag" that most talk about is when you are in a low RPM situation and you apply full throttle without downshifting. This is where you won't notice much coming from the supercharger for a few moments. You need to spin up the blower initially and it goes from there, so in other words, you need to either drop down to a lower gear for a jump in RPM or if it's an automatic you are driving, just floor it. Once your RPM's jump up, just hold on.
I don't know about books, but you can certainly find a wealth of information on the web about whatever you want.
By the way, what kind of car do you have??
imported_Aurora40
New member
the other pc said:
Small two cents. I don't think this is that common. The 3800 S/C is in general a pretty durable engine. Our GS has about 130,000 miles on it and it's still running nicely.